As tea aficionados love to point out, there are many parallels between tea and wine. While we typically draw this comparison between aspects of cultivation and culture, it is also applicable to flavor. Both tea and wine can display a wide variety of flavors, ranging from smooth and sweet to dry and bitter. And while bitterness is rarely a sign of quality, a practiced palate can appreciate even “undesirable” flavors as an integral component of the balanced whole.
Often, the flavor of bitterness is conflated with astringency, or the dry texture some teas leave in the mouth. In fact, these two components have totally separate origins and effects. Today, we’ll clarify how they differ, and what they signify about the quality of the tea leaves.
Bitterness is recognized as one of the five basic flavors detectable by the human palate. To our evolutionary ancestors, bitter flavors are thought to have signified poisonous substances. Thus, the palate’s natural reaction is usually distaste. In fact, the excessive bitterness of unprocessed tea leaves relegated tea to the role of herbal medicine for much of its early history. Since then, Chinese tea crafters have spent several centuries refining the process of growing and crafting tea to reduce the level of bitterness in the brew.
Today, chemical analysis has linked bitter flavors in the leaf to high levels of methylxanthines, a category that includes caffeine, as well as other compounds like theobromine. These compounds are not only a flavor deterrent to the human palate, but also repel predatory insects. Thus they are most prevalent in fast-growing tea plants cultivated in hot, humid climates, where the pest population is large. Teas grown in less hospitable regions, like high elevation tea gardens, are less threatened by insect populations and develop fewer bitter compounds.
By contrast, astringency is a feeling of dryness in the mouth. It is not, in fact, a flavor perceived by the taste buds. While the sensation may be felt on the tongue, it is also obvious in the cheeks and throat. It can make the tongue feel rough, or induce puckering in the cheeks. It can take up to 15 seconds for the feeling to manifest, and it is known to be cumulative, becoming more pronounced with repeated sips. This unique effect is caused by the presence of polyphenols, both in tea and in many other foods and beverages, like wine or unripe fruit. Polyphenols, as a category, include all the lauded antioxidants found in the tea leaf.
Astringency is not always a desirable flavor component. Notably, a lack of astringency is a sign of high quality in white, green, and formosa oolong teas. But it is also often appreciated by seasoned palates. It is, for instance, the same sensation that connoisseurs covet in a “dry” wine. Despite the association between astringency and bitterness, it can also accompany other flavors, like natural sweetness.
This brings us to a central component of Chinese tea appreciation: the "finish". In Chinese, hui gan translates most directly as “returning sweetness”. Practically, this is the flavor that lingers in the back of the mouth and throat, ideally lasting long after the tea is swallowed. A tea that has a strong finish is necessarily complex, with flavors that change over the course of the experience, and generally considered to be high quality.
Bitterness, while it may be present, does not necessarily contribute to the intensity of the finish. Astringency, though, is often closely associated with lasting flavor. This concept is clearly illustrated in the oolongs of Phoenix Mountain, in Guangdong. Bred for specific fruit or flower fragrances, Phoenix oolong leaves are plucked from tea trees as old as 100 years or more. The trees produce fewer leaves as they age, but each leaf contains a higher concentration of the nutrients and chemical compounds of the plant.
Carefully cultivated for flavor and grown at high elevations, where pest threats are low, Phoenix oolongs are not often bitter. Brewed with a light hand, they are often astonishingly sweet, with distinct fragrances of honey or citrus. But brewed at higher concentrations (as is common in Guangdong), these teas can be extremely astringent. Locals in the region, who drink this type of tea daily, appreciate this characteristic. The slow, cumulative build of astringency contributes and elongates the effect of the hui gan.
In short, for some styles of tea, astringency is not only allowable, but even desired and cultivated. By contrast, bitterness is usually a sign of mass production, and is rarely associated with quality tea leaves. Wine drinkers are probably not surprised.
Next time a tea makes your cheeks pucker, take a moment to notice and distinguish these characteristics of flavor. You may soon be savoring the complexity instead of cringing.
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